Prostaglandins are thought to be important mediators of physiologic and pharmacologic processes in the eye. The synthesis of prostaglandins is a complicated process that progresses from fatty acid precursors through endoperoxide and thromboxane intermediates in many tissues. In some tissues the endoperoxide and thromboxane compounds may be more potent or even have an opposite effect from the major prostaglandin synthesized. The present project is designed to study the pathways of prostaglandin synthesis in the eye. The perfused isolated cat eye will be exposed to a variety of stimuli (hormones, catecholamines, ischemia, vasoactive substances, inflammation). The venous effluent will be continuously assayed for prostaglandin products by superfusion of a series of smooth muscle strips. In this way, a dose response and temporal relationship between the stimulus and the prostaglandin synthesis or release will be tested in this system to determine their relative potency and mechanism of action. Chromatography will be utilized for a biochemical confirmation of the bioassay procedure. A better understanding of the pathways of prostaglandin synthesis will lead to a better understanding of physiologic and pathologic processes in the eye (aqueous formation, uveitis). This will also help in the development of better ocular anti-inflammatory agents.